Apparatus for testing the hardness of materials



2 Dec" 25 w 3 R. L. sMiTH ET AL APPARATUS FOR TESTING THE HARDNESS OF' MATERIALS Um. 25 T1923. TSZl R. l.. SMITH ET AL.

APPARATUS FOR TESTING THE HARDNESS -OF MATERIALS Filed May 16, 1925 2 Sheets-Sheet 2 g mgm @3a/Gam@ LOW wif www@ Patented Der, 2E, T923.,

UNTTEE STATES 'TAT/@EET PATENT @EETCCEO ROlBmT LOW SMITH AND GEORGE EDWARD SANDLAND, OF ERTH, ENGLAND, AS- SIGNORS TO VICKERS LIMITED, E WESTMINSTER, LONDON, ENGLAND.

APPRATUS FOR TESTING THE HARDNESS OF MATERIALS.

Application led May 16, 1923.

T o all whom t may conce/vt.'

Be it known that we, ROBERT Low SMITH and GEORGE EDWARD SANDLAND, both subjects of the King of Great Britain, residing at Erith Works. Erith, in the county' of Kent, England, have invented certain new and useful Improvements in or Relating to Apparatus for Testing the Hardness of Materials, of which the, following is a specificalo tion.

This invention relates to apparatus for testing the hardness of materials and more particularly to apparatus of the kind in which a definite load pressure is applied to the material to be tested by a member of small dimensions, the relative hardness of the material being gauged by measuring the size of the indentation made by the said small member in the material when a given a0 Weight is applied.

In apparatus of this kind it has been proposed to employ a rotatable cam orV its equivalent for the purpose of applying pressure gradually to the material being tested,

maintaining the pressure or a period of time and thereafter removing the same. ln such apparatus, however, the time period which elapses before the load is removed has either not been determined automatically, and being under the control of the operator has therefore been a variable' factor, or else in cases where the time period has been determined automatically the work or material to which the pressure is applied, has been moved upwards against the intluence of the load so that the weights which apply the pressure must actually be lifted by the work.

According to the present invention we prefer to employ an apparatus in which the work or material which is being tested is supported upon 4a platform or table which is stationary during the application of the load, the pressure being applied gradually to the stationary material and, after the pressure has been maintained for a p redetermined period of time, being automatically removed.

To this end we may provide a slidable rod or the like which is adapted to engage or to lie in the path of movement of apressure applying lever which carries a weight at one end and acts upon the pressure applying member at its other end, together With a rotatable cam or its equivalent which Serial No. 639,229.

controls the reciprocating movement of the said rod in such manner that it is caused or permitted to move gradually out of the path of movement of the said lever so as to allow the latter to apply pressure to the work and which, after a predetermined interval of time, restores the weighted lever to its original position so as to remove automatically the pressure from the work.

The said cam .may be adapted tov be rotated by hand against the action lof a counterweight to bring the aforesaid rod into position to restrain the movement of the weighted lever or the counterweight may be raised without rotating the cam, the latter being held in position bv a pawl, so that, when released, the counterweight will eiect the rotation of the cam, thereby permitting the rod to move out of the path of thel said lever and thereafter restoring the rod to its initial starting position, the rotation of the cam being brakedby a dashpot or its equivalent to ensure a suitable interval of time elapsing before the cam again restores the slidable rod to its initial position and removes the pressure of the lever from the Work.

Although it has been proposed to employ a diamond in connection with other methods of testing the hardness of materials,` we have discovered that in indentation tests in which the load is applied, maintained for a predetermined interval of time and thereafter automatically removed a diamond, either shaped, or uncut or natural, is the most suitable substance for making the impression or indentation in the work, but hardened steel or other hard material may be used in certain cases.

By means of the present invention we are able to ensure not only constancy of the time element both in the application and duration of the load, but also to eliminate inertia and to render possible the testing of intensely hard materials with a minimum of distortion or displacement so that the finished work is undamaged by the test. Moreover, and especially in cases where a i diamond is employed, the impression or indentation made in the work is so small and the load applied is so light that very small objects may be tested. Consequently, and by means of the present apparatus the range of work is greatly increased, it being os-` sible to subject to tests a variety of articles main frame of the machine.

entirely outside the capacity of apparatus using the ordinary ball test.

It will t-hus be seen that the present apparatus enables a novel method to be carried on for testing the' hardness of materials said method consisting in supporting the work to be tested upon a platform or table which is stationary while the load is being applied, the pressure being thereafter applied gradually to the stationary work through the intermediary of a member of small dimensions and maintained for a predetermined period o f time before being automatically removed.

In order that the said invention may be clearly understood and readily carried into effect the same will now' be described more fully with reference to the accompanying drawings which show by way of example one embodiment of an apparatus constructed according to the present invent-ion and 1n which Figure .1 is a side elevation,

Figure 1a is an enlarged View of a detail,

Figure 2 is a plan,

Figure 3 is a part sectional front elevation,

Figure 4f is a rear sectional elevation, and

Figure 5 is a section through the line A, A of Figure 4, the connecting rod being removed so as to show other parts more clearly.

1 is a main frame of the machine. 2 is the platform or table, upon which the work which is to be tested is supported. the platform 2 being mounted upon guides on the main frame of the machine and being free to move in a. vertical direc-tion under the influence of a screw threaded rod 3 adapted to be rotated through bevel gearing 4 by means of a handle 5 so that the platform may be raised and lowered on the said rod 3 as desired. 6 is the pressure applying lever which is pivoted between lugs 7, 7 on a horizontal arm 8 forming part of the The said lever 6 is provided towards its front end with a small projection or concial ended lug 9 constituted by a block of hardened steel inserted in a recess in the lever 6, the said projection 9 being adapted to bear, when the movement of the lever is unrestrained upon the upper end of a thrust rod 10, the lower end of which engages within a plunger 11, which is slidably mounted within a bearng 11a in the arm 8 of the machine, the lower end of said plunger 11 carrying the member 12 of small dimensions for making the indentation or impreion in the work. In the example shown the member 12 is constituted by a diamond, but hardened steel or other hard material may be used in certain casesl To the other end of the pressure applying lever 6 a rod 13 is connected to which suitable weights 14,

temeer.

14 are adapted to be attached, a spring 15 being interposed as shown betweenthe rod 13 and the lever 6. Mounted so as to have vertical reciprocating movement on the frame of the machine, is a rod 16, the upper end of which bears against the underside of the pressure applying lever 6 and holds the same so that the projection or lug 9 is raised slight-ly out of contact with the/ upper end of the thrust rod 10 when the same is raised to the position given by the indicator hereinafter referred to. In the example shown the rod 16 is constituted by an upper hardened steel portion 161 having a hood-like part 162 and a lower portion 163, a buffer spring 164 being provided and located in recesses in the parts 161 and 162. At the lower end of the part 162 a roller 165 is provided which is adapted to run upon the surface of the rotatable cam 17 which latter is connected to or formed integral with a pully wheel 18 around which a wire or cable 19 is wound, the

free end of the cable passing over a guide roller 20 and being connected to a counterweight 21. ln the example shown the periphery of the pulley wheel 18, is provided with a single tooth 181 and is rotatably mounted upon a spindle 22. Mounted upon a second spindle 221 is a' part 26 which is connected to the cam 17 by means of a pin 27, so that the parts 17, 18, 26, 27, 22 and 221 form a crank-like arrangement.

handle23 ,and 4gear wheels 23 and 23b are provided so that by rotating the handle- 23 and consequently the pulley 18 the cam 17 can be brought into such position that the rod 16 is raised to its upper position. a pawl 24 pivotally mounted upon the frame of the machine and actuated by a handle 25 being adapted to engage with the ratchet tooth 181 on the pully 18, so as to hold the cam 17 in the aforesaid position. It will thus be seen that the cam 17A will stop in one position only and the position of the ratchet tooth 181 is such that this occurs when the plunger 16 is supporting the lever 6 at its highest or normal position.

1t will be understood that the primary object of the handle 23 and its associated gearing 23 and 23" is to raise the counterweight 21. and although in the example illustrated in the drawings the cam 17 is directly connected tothe pulley 18, the parts could be so arranged as to permit the pulley to be rotated and the counterweight to be raised '.10b of the indicator coincide.

Largest the piston 29 being provided with a needle valve 31 and a non-return valve 32. ln view of this arrangement and when the parts are in the raised position shown, the disengagement of the pawl 24 by means of the handle will release the cam 17, while the piston and cylinder 29 and 30 will act as a dashpot so as to brake the movement of the same. As the cam 17 rotates the rod 16 is gradually permitted to move downwards away from the lever 6 so that the projection 9 bears upon the upper end of the plunger 10 and pressure is transmitted through the diamond 12 to the work. The shape of the cam ensures the pressure on the work being maintained for a predetermined interval and the arrangement of the parts is such that whenA the cam 17 has completed a full rotationl the rod 16 has again been raised to normal position and the pressure exerted through the lever 6, conical ended lug 9 and plunger 10 is automatically removed. y

Referring more particularly to Figure 1 101 is a ring provided at the upper end o the plunger 11 which is adapted to carry a member l()2 having a notch 1()a forming part of an indicator for indicating the correct height of the diamond holder or plunger 11. 103 is the other member of the indicator which is similarly provided with a notch 10b and carried either by the lugs 7, 7 or by the part 8. In carrying out a test the work is placed upon the platform 2, which is raised until contact is made with the diamond 12. When the stage or platform 2 is raised still further the diamond 12 with its holder or plunger 11 and thrust rod 10 are also lifted until the lines l()a and rlhe lug 9 in this position of the parts is just clear of its seating on the plunger 10.

For the purpose of facilitating inspect-ion of the indentation or impressioir'made by the diamond a microscope 33 is provided carried by an arm 34 pivotally attached at 35 to the face of the arm 8, a spring 36 being also provided so that the arin 34 which carries the microscope 33 can be held in one or other of thetwo required positions. To this end the arm 34 has a projection or lug 341 at its upper end upon which two flats, cams, or their equivalent are provided, the spring 36 normally bearing upon the uppermost of these cams, thus serving to restrain the rotation of the arm 34 and locking the microscope in its upper or lower position, as desired. The arm 34 which carries the microscope 33 may, if desired, be made in two parts 34a and 34h, each formed with an elongated slot 34, the parts-being held together by a screw 34d so that'by loosening the screw 34d the parts 34a and 34b can be moved relatively to each other for purposes of line adjustment, while coarse adjustment can be eected by moving the platform 2 by means of the adjusting screw 3. An electric lamp 37 is provided and located in a socket or housing 38 in the arm 8 of the machine,the lamp being provided to facilitate examination by the microscope 33. rlhe light of the lamp 37 is directed through a lens 38a on to the usual clear glass reflector 33a in the microscope 33 and thence to a reflecting prism 39. An accumulator battei'y or other source of electric current 40 may be provided and supported as shown on the bed plate of the machine. Laterally 'projecting lugs 41, 41 may also be provided on the arm of the machine for accommodating the weights 14 so that the whole machine forms a portable unit.

What we 'claim and desire to secure by Letters Patent of the United States is l. Apparatus for testing the hardness of materials comprising a pressure applying lever, a weight at one end of said lever, a pressure applying member near the other end of said lever, a slidable member .adapted to lie in the path of movement of said pressure applying lever, means controlling the movement of saidy slidable member and causing the same to move automatically and gradually out of the path ofinovement of said pressure applying lever to allow the latter, through the intermediary of the pressure applying member, to apply pressure gradually to the work and means acting automatically to restore the pressure apply` ing lever to its original position, after the lapse of a predetermined interval of time, and to remove the pressure fromthe work.

2. Apparatus forI testing the hardness of materials comprising a weighted pressure applying lever adapted to apply pressure to the work, a counterweight, a slidable member subjected to the influence of the counterweight, a cam member controlling said slidable member, means for releasing said counterweight, and means controlled by Said counterweight for'effecting the rotation of said cam and permitting said slidable member to move out of the path of the pressure applying lever to allow pressure to be applied to the work and automatically restoring said member to its initial position after a predetermined interval of time so as to remove the pressure from the work.

3. Apparatus for testing the hardness of materials comprising a weighted pressure applying lever, a slidable restraining meinber, cam means controlling said restraining member,` a counterweight, means for releasing said counterweight, means controlled by said counterweight for eli'ecting the rotation of said cam means and permitting said slidable member to move out of the path of said pressure applying lever to allow pressure to be applied to the work and thereafter restoring said member to its initial position so as to removethe pressure from the work, and a delay action device con trolling the speed of rotation of said cam 'member and ensurin the lapse of a suitable l of materials comprising a member adapted to make an indentation in the material, a lever cooperating with the indentation forming member and adapted to cause pressure to be brought to bear thereon and thereby elect its movement in one direction, and means for automatically removin the pressure from the lever after a pre eter mined interval of time.

5. An ,apparatus for testing the hardness of materials comprising a member adapted to make an indentation in the material, a lever cooperating with said member to cause pressure to be brought. to bear thereon, a second member cooperating with the lever and means for automatically raising and lowering said second member at predetermined'intervals, whereby the duration of the pressure on the indentation'member is automatically controlled.

6. An apparatus for testing the hardness of materials comprising a member adapted to make an indentation in the material, a lever cooperating with said member to cause pressure to be brought to bear thereon, a second member coacting with said lever, and

Lerenti means for actuating said second member whereby the duration of pressure on the indent-ation member is automatically regulated.

7 An apparatus for testing the hardness of materials comprising a member adapted to make an indentation in the material, a

lever cooperating with said member to cause pressure to be brought to bear thereon, a second member engaging said lever and adapted to raise and lower it, whereby the duration of pressure upon the indentation member is controlled, and cam means for automatically raising and lowering said second member at predetermined intervals of time.

8. An apparatus for testing the hardness of materials comprising a main frame, a work-supporting latform carried thereon, an indentation orming member Ireciprocably mounted in said main frame, a lever pivoted to the main frame and having a portion thereof coacting with the indentav tion forming member toI cause its reciprocation in one direction, said lever having a counterweight, at one end thereof and a pressure applying weightv at its -other end, and means between the pressure applying weight and the indentation forming member for automatically .controlling the duration of the pressure on the indentation forming member.

ROBERT LO`W SMITH,

GEORGE EDWARD SANDLAND. 

